The present invention is an improvement over the construction disclosed in U.S. Pat. No. 3,770,939, issued Nov. 6, 1973, to Leonard Dennis Kokjohn for Electric Heating Assemblies, and assigned to the assignee of the present application.
In the Kokjohn patent, a thermostat is mounted between two spaced strips which extend crosswise of a pair of frame side arms. The thermostat has a heat sensor directed toward and positioned in close proximity to an active heating portion of the resistance coil so as to be extremely sensitive to any abnormally high temperature and quickly interrupt electrical current to the heater.
Heating assemblies corresponding to the Kokjohn disclosure are still being used and perform satisfactorily. However, they have one inherent fault in that the thermostat might be improperly installed, especially after service work, so that its heat sensor is directed away from the active heating portion of the coil, instead of directed toward such portion, and this materially affects the sensitivity of the thermostat.
My invention insures that the thermostat will at all times be installed in proper manner so that its heat sensor is in predetermined relation with an active heating portion of the resistor coil. Specifically, this is accomplished by fitting a tab extending from a thermostat terminal into an opening in an insulator bushing, the tab fitting in the opening in only one way, and the bushing being held against substantial rotation.